The present disclosure relates to a measuring device for measuring a physiological parameter of an aspirate. The measuring device comprises at least one physiological parameter sensor element.
In clinical medicine there are many situations where detecting the location of a medical tube within a patient is important. For example, when positioning a feeding tube through the nose of a patient, it is essential that the end of the feeding tube passes into the patient's esophagus and not into the lung/trachea. If the end of the feeding tube is positioned in the trachea rather than in the stomach, aspiration of the feeding solution into the patient's lungs may occur. Further, when positioning a medical tube through the nose of a patient into the patient's trachea/lung, it has to be checked if the end of the medical tube really passes into the lung/trachea and not into the esophagus. In this regard, devices are known for detecting CO2 values of aspirates in order to check if a medical tube is in the trachea or in the esophagus.
Improper positioning of enteral feeding tubes into the trachea resulting in respiratory distress or death has been described in the literature. In practice, tube position should be checked following initial insertion, before administering each feed, before giving medication, following vomiting, retching or coughing or if there is evidence of tube displacement, for example, if the tape is loose or the visible tube appears longer of kinked.
Currently, the location of a medical tube within the body of a patient is routinely detected by the use of imaging equipment, such as X-ray. However, such a procedure requires transportation of the patient to an X-ray facility. This is both inconvenient and costly and is particularly stressful in those instances where the medical tube has repeatedly to be repositioned, thus requiring repeated reinsertion and X-rays.
US 2004/0158138 A1 discloses an implantable monitoring probe having a sensor for detecting pH and a transmitter for transmitting data to an external receiver. The probe is implanted in the esophagus or other body lumen of a patient to aid in the detection of gastroesophageal reflux disease. US 2003/0040671 A1 discloses a medical tube for insertion into a tracheal tube of a patient wherein the medical tube includes a pH sensing element. U.S. Pat. No. 7,052,474 B2 discloses a pharyngoesophageal monitoring system that includes multiple internal references probes detecting acid reflux and monitoring pH levels.
However, these measuring devices have to be inserted into a medical tube and in the patient's body. To evaluate the measured value further equipment, e.g. transmitters and data recorders, is necessary. Such equipment is extensive and costly. The current practice by clinicians of obtaining the pH value of a patient's aspirate is to draw up aspirate fluid with a syringe and place a drop of this fluid onto a pH indicator strip. However, this procedure is critical for clinicians as regards the bacteria contained in the aspirate fluid.